Di and tri(hydrocarbylammonium)trithiocyanurate and lubricating oil compositions containing same

ABSTRACT

Di- and tri-C8-C24 hydrocarbyl ammonium trithiocyanurate and a lubricating oil composition containing said di- or trihydrocarbylammonium thithiocyanurate having improved load carrying properties.

United States Patent 1191 Nebzydoski Nov. 19, 1974 DI AND TRI (HYDROCARBYLAMMONIUM) TRITHIOCYANURATE AND LUBRICATING OIL COMPOSITIONS CONTAINING SAME [52] U.S. Cl 252/33.6, 252/47, 260/248 CS [51] Int. Cl. ClOm 1/38, ClOm 1/32 [58] Field of Search 252/33.6, 47; 260/248 CS [56] References Cited UNITED STATES PATENTS 2,223,130 11/1940 Prutton ..252/33.6

4/1954 Loughran et a1. 252/47 12/1973 Nakamura et a1. 260/248 CS Primary Examiner-W. Cannon Attorney, Agent, or Firm-T. H. Whaley; C. G. Ries [5 7] ABSTRACT Diand t1'i-C -C hydrocarbyl ammonium trithiocyanurate and a lubricating oil composition containing said dior trihydrocarbylammonium thithiocyanurate having improved load carrying properties 10 Claims, No Drawings DI AND TRI (HYDROCARBYLAMMONIUM) TRITHIOCYANURATE AND LUBRICATING OIL COMPOSITIONS CONTAINING SAME BACKGROUND OF THE INVENTION Field of the Invention This invention relates to a novel hydrocarbylammonium trithiocyanurate produced by combining 2 to 3 moles of a C to C hydrocarbylamine with trithiocyanuric acid. These compounds can be described as the di-and trihydrocarbylamine salts of trithiocyanuric acid.

The diand trihydrocarbylammonium trithiocyanurates are represented by the following formula:

s l /C N \N at em] in which R represents hydrogen or a hydrocarbyl radical having from 8 to 24 carbon atoins at least one R being a hydrocarbyl radical and n has a value from to This invention also relates to a novel lubricating oil composition containing the above-described hydrocarbylammonium trithiocyanurate.

SUMMARY OF THE INVENTION In general, the di-and trihydrocarbylammonium trithiocyanurates are represented by the following formula:

c i N/ N in which R is hydrogen or a hydrocarbyl radical having from 6 to 24 carbon atoms at least one R being a hydrocarbyl radical and n has a value from 0 to l. The so defined hydrocarbylammonium trithiocyanurates result:

(RNlLz):

in which R is a hydrocarbyl radical having from about 12 to about 22 carbon atoms.

Another preferred class of hydrocarbylammonium trithiocyanurates are represented by the formula:

in which R is a hydrocarbyl radical having from about 12 to about 22 carbon atoms. The hydrocarbyl radicals represented by R in all of the formulas above are monovalent hydrocarbyl or hydrocarbon radicals and include alkyl, aralkyl, aryl, alkaryl and cycloalkyl radicals having the prescribed carbon chain length.

A more preferred hydrocarbylammonium trithiocyanurate is that formed from tertiary alkyl primary amines wherein 2 or 3 moles of a tertiary alkyl primary amine has been reacted with trithiocyanuric acid.

The hydrocarbylammonium trithiocyanurates are conveniently prepared in a 2-step process beginning with cyanuric chloride. In the first step of this process, cyanuric chloride and thiourea are reacted in the presence of an inert solvent at a moderate temperature, generally the reflux temperature of the solvent to produce a solid reaction product. The solid product is filtered off and dissolved in an alkali solution, such as an aqueous potassium hydroxide solution, which is then acidified with a mineral acid, such as concentrated hydrochloric acid, to produce cyanuric acid, a pale yellow N N s ci-b LL01 a mob-N112 s-c NH-1 o1- 1 NH? N \N NlIz Cl- (LS-JY b-s- .--NH2 (a) NnOll N112 N (h) 1101 (2) in N N N801 to NII:(1EN susu Its-ii b-sli f N where n equals or 1.

The reactants are heated at an elevated temperature ranging up to 220 to 260F. with adequate stirring. On completion of this reaction, the product is diluted with methanol or ethanol, filtered, and the salt recovered from the hydrocarbon solvent generally in the form of a yellow oil.

As indicated above, the hydrocarbylammonium trithiocyanurate employed in this invention will contain 2 to 3 moieties of the hydrocarbylamine per mole ofthe trithiocyanurlc acid moiety. The hydrocarbylamine is represented by the formula RNH in which R represents a hydrocarbyl radical having from 8 to 24 carbon atoms. Preferred amines are those in which R is a hydrocarbyl radical having from about 12 to 22 carbon atoms. The hydrocarbyl radical can be any monovalent organic radical, such as an alkyl, aryl, cycloalkyl, alkaryl or aralkyl hydrocarbon radical of the indicated carbon chain length. The alkyl radical can be a straightchain or branchedchain hydrocarbon radical although it is preferred to employ amines in which the hydrocarbyl radical is a tertiary alkyl saturated hydrocarbon radical.

The following examples illustrate the preparation of typical hydrocarbylammonium trithiocyanurates according to this invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS EXAMPLE I Tri (t-C to C primary ammonium) trithiocyanurate l8.45 parts of cyanuric chloride, 22.8 parts of thiourea and 400 parts of acetone were refluxed for 2 hours. The solid product was filtered off and dissolved in 170 parts of potassium hydroxide solution (ll grams H O/ grams KOH). This mixture was acidified to a pH of l with concentrated hydrochloric acid yielding as product a pale yellow solid having a melting point greater than 300C. The infrared spectrum of this sample was taken and found to be identical to that of an authentic sample.

5.31 parts of trithiocyanuric acid and 28.4 parts of t-C to C alkyl primary amine were heated for about 2 hours at 220F. with stirring. The reaction mixture was cooled, diluted with 50 parts of methanol, filtered and concentrated yielding the product as a yellow oil. This product conformed to the following formula:

(RNHa):

in.which R represents a t-C to C aliphatic hydrocarbon radical. This salt had a nitrogen content of 7.6 percent (calc. 7.6) and a sulfur content of 8.4 percent (calc. 8.6).

EXAMPLE n Tri(t-C -C alkyl primary ammonium) trithiocyanurate 2.95 parts of trithiocyanuric acid and 9.55 parts of t-C -C primary alkylamine were heated for about 2 hours at about 250F. with stirring. The reaction product was cooled, diluted with ethanol, filtered and concentrated yielding 11.9 parts of tri(t-C ,-C alkyl primary ammonium) trithiocyanurate as a yellow oil. This product has a nitrogen content of 11.7 percent (calc. 12.0).

EXAMPLE lll Di-(t-C -C alkyl primary ammonium) trithiocyanurate 5.3l parts of trithiocyanuric acid and 18.9 parts of t-clgcgz alkyl primary amine were reacted as in Example l above to form di(t-C, -C alkyl primary ammonium) trithiocyanurate having a nitrogen content of 9.6 (calc. 8.7) and a sulfur content of 11.5 (calc 11.9).

Many other oil-soluble diand trihydrocarbylamamonium trithiocyanurates can be prepared within the scope of this invention following the above procedure which are useful for enhancing the loadcarrying properties of a lubricating oil composition. Additional examples of these compounds include diand tri (octadecylammonium) trithiocyanurate, diand tri- (trioctadecyl-arnmonium) trithiocyanurate, diand tri- (dioctadecyl ammonium) trithiocyanurate, diand tri- (di-t-C -C alkyl ammonium) trithio cyanurate, diand tri- (tri-t-C -C alkylammonium) trithiocyanurate, diand tri- (hexadecylammonium) trithiocyanurate, diand tri- (declyammonium) trithiocyanurate, diand tri-(eicosylammonium) trithiocyanurate, diand tri-(dodecylammonium) trithiocyanurate, and diand tri-(octylammonium) trithiocyanurate,

The diand tri-(hydro carbylammonium) trithiocyanurates of this invention are valuable for enhancing the load-carrying properties of lubricating oils. In general, the prescribed compounds can be employed in both mineral and synthetic lubricating oil compositions usually at a concentration ranging from about 0.001 to about 0.5 weight percent with the preferred concentration being from about 0.01 to 0.3 percent. A suitable mineral lubricating oil base will have an SUS viscosity at F. ranging from about 50 to 1,000 with the preferred viscosity range being from 70 to 300 SUS at 100F.

The prescribed additive compounds of this invention are particularly efficacious in synthetic ester base lubricating oil compositions and were employed in a typical fully formulated synthetic ester base lubricating oil which was tested for its load-carrying porperties as well as for its oxidation-corrosion resistance.

The base fluid component of this type lubricant is an ester-base fluid prepared from pentaerythritol or trimethylolpropane and a mixture of hydrocarbyl monocarboxylic acids. Polypentaerythritols, such as dipentaerythritol, tripentaerythritol and tetra-pentaerythritol can also be employed in the reaction to prepare the base oil.

The hydrocarbon monocarboxylic acids which are used to form the ester-base fluid include the straightchain and branched-chain aliphatic acids, cycloaliphatic acids and aromatic acids as well as mixtures of these acids. The acids employed have from about 2 to 18 carbon atoms per molecule, and preferably from about 5 to carbon atoms. Examples of suitable specific acids are acetic, propionic, butyric, valeric, isovaleric, caproic, decanoic, cyclohexanoic, benzoic acid, phenylacetic, tertiary-butylacetic acid and 2- ethylhexanoic acid.

In general, the acids are reacted in proportions leading to a completely esterified pentaerythritol or trimethylolpropane with the preferred ester bases being the pentaerythritol tetraesters. Examples of such commercially available tetraesters include pentaerythritol tetracaproate, which is prepared from purified pentaerythritol and crude caproic acid containing other C monobasic acids. Another suitable tetraester is prepared from a technical grade pentaerythritol and a mixture of acids comprising 38 percent valeric, 13 percent 2-methyl pentanoic, 32 percent octanoic and 17 percent pelargonic acids. Another effective ester is the triester of trimethylolpropane in which the trimethylolpropane is esterified with a monobasic acid mixture consisting of 2 percent valeric, 9 percent caproic, 13 percent heptanoic, 7 percent octanoic, 3 percent caprylic, 65 percent pelargonic and 1 percent capric acids. Trimethylolpropane triheptanoate is also a suitable ester base.

The ester base comprises the major portion of the fully formulated synthetic ester base lubricating oil composition. In general, this ester base fluid is present in concentrations from about 90 to 98 percent of the composition.

In addition to the essential dior tri- (hydrocarbylammonium) trithiocyanurate component of the lubricating oil composition, synthetic ester base lubricants will generally contain additional additives to impart oxidation and corrosion resistance. metal deactivators and the like in order to provide a superior lubricant composition.

A valuable oxidation and corrosion inhibitor is an alkyl or alkaryl phenyl naphthylamine represented by the formula:

11 it 1% \J in which R is an alkyl or alkaryl radical having from about 3 to 12 carbon atoms. This radical can be a straight or branched chain alkyl radical with the tertiary alkyl structure being preferred or it can be an alkylaryl radical. The naphthylamine can be either an alpha or beta naphthylamine. Specific effective compounds of this class include N-(p-t-octylphenyU- a -naphthylamine, N- (4-cumylphenyl)-6-cumyl-B- naphthylamine, N-(p-t-octylphenyh- B-naphthylamine and the corresponding p-t-dodecylphenyl, p-tbutylphenyl, and p-dodecylphenyl-a and -B -naphthylamines. The preferred naphthylamines are those in which R is a tertiary alkyl radical having from 6 to 10 carbon atoms with the preferred concentration of this component being from about 0.5 to 2.5 percent.

Another valuable oxidation inhibitor of the ester base lubricating oil composition is a dialkyldiphenylamine. These compounds are represented by the formula:

III N- R in which the R is an alkyl radical having from about 3 to 12 carbon atoms. Suitable alkylamines include dioctyldiphenylamine, didecyldiphenylamine and similar compounds. The preferred class of dialkyl diphenylamines are those in which R is an alkyl radical having from 8 to 10 carbon atoms. Dooctyldiphenylamine is the preferred compound and the effective concentration is from 0.5 to 2.0 percent.

. Another valuable component of an ester base lubricating oil composition is a hydrocarbylphosphate ester, more specifically a trihydrocarbyl phosphate having the formula (R0) P0 in which R is a hydrocarbyl radical, i.e., an alkyl, aryl, alkaryl, cycloalkyl or aralkyl radical or mixture thereof having from 2 to 12 carbon atoms and preferably from 4 to 8 carbon atoms. Effective specific compounds include tricresylphosphate, cresyl diphenyl-phosphate, triphenylphosphate, tributylphosphate, tri(2-ethylhexyl)-phosphate and tricyclohexyl phosphate. These compounds are generally effective at a concentration ranging from about 0.5 to 5 weight percent of the lubricant composition.

An optional component of the lubricant is a metal deactivator, which is commonly employed in an ester base lubricating oil composition. An effective metal deactivator is a polyhydroxy-substituted anthraquinone inhibitor represented by the formula:

in which X, Y and Z each represent hydrogen or a hydroxyl group and at least one of these is a hydroxyl group. Examples of effective polyhydroxy-substituted anthraquinones include l,4-dihydroxyanthraquinone, l,5-dihydroxyanthraquinone, l,2,4-trihydroxyanthraquinone and l,2,5,8-tetrahydroxyanthraquinone. In general, this component is employed in a concentration ranging from about 0.04 to 2.0 weight percent of the lubricating oil composition with the preferred concentration being from 0.05 to 0.25 weight percent.

The load carrying properties of lubricants containing trithiocyanurates was determined by preparing oil compositions and subjecting them to load-carrying tests in the Ryder Gear Test. Thelubricating oil compositions were also tested for their oxidation and corrosion resistance in the 425F/48 I-Ir. Oxidation and Corrosion Test which was conducted in accordance with Standard No. 791a (issued Dec. 31, 196]) except-for modifications to conform to Pratt and Whitney 521C Specifications. The bath temperature is maintained at 425F. i lF. instead of at 250F. and the test is conducted for a period of 48 hours instead of 168 hours as specified in the original test.

The ester base oil employed in preparing Base Fluids A and B belowcomprised pentaerythritol containing a minor amount of dipentaerythritol esterified with mixtures of fatty acids. This ester base (Hercules L-39) consisted of a technical grade pentaerythritol ester made from a mixture of carboxylic acids consisting of (mole percent).

Base Fluid A consisted of 95.4 weight percent of the foregoing ester base plus 1.0 weight percent dioctyldiphenylamine, 1.5 wt. percent N-(4-tert.octylphenyl)-anaphthylamine 2.0 wt. percent tricresylphosphate, and 0.1 wt. percent of quinizarin. This Base Fluid has an average Ryder Gear Test Failure Load of about 2,650 PP Base Fluid B was similar to Base Fluid A but contained N-(4-cumylphenyl)-6-cumyl)-2-napthylamine in place of the N-(4-tert. octylphenyl)-a-naphthylamine. This Base Fluid has an average Ryder Gear Test Failure Load of about 2,650 ppi.

Base Fluid C is a reference oil used in the US. Navys XAS2354 specification (Hercolube A) as a comparison oil for evaluating high load oils. According to the US. Navy specifications, a high gear load oil passes this test ifit exhibits a load carrying capacity of 144 percent (two runs) or 135 percent (six run average) over the reference oil.

The results of the Ryder Gear Load Carrying Test and the Oxidation-Corrosion Test are set forth in the table below:

TABLE I at aw). J

(R NlDa-a in which R is hydrogen or a hydrocarbyl radical having from about 8 to 24 carbon atoms at least one R being a hydrocarbyl radical and n has a value from 0 to l.

2. A lubricating oil composition according to claim 1 in which said hydrocarbyl radical has from 12 to 22 carbon atoms.

3. A lubricating oil composition according to claim 1 in which said hydrocarbyl radical is a tertiary alkyl hydrocarbon radical.

4. A lubricating oil composition according to claim 1 in which said hydrocarbylammonium trithiocyanurate is tri(t-C, -C alkyl primary ammonium) trithiocyanurate.

5. A lubricating oil composition according to claim 1 in which said hydrocarbylammonium trithiocyanurate is tri(t-C -C alkyl primary ammonium, trithiocyanurate.

6. A lubricating oil composition according to claim 1 in which said hydrocarbylammonium trithiocyanurate is di(t-C, -C alkyl primary ammonium, trithiocyanurate.

7. A lubricating oil composition according to claim 1 in which said hydrocarbylammonium trithiocyanurate is di(t-C -C alkyl primary ammonium) trithiocyanurate.

EVALUATION OF Dl- AND TRI-(HYDROCARBYLAMMONIUM) TRITI-IIOCYANURATES RYDER GEAR TEST Additive & FAILURE LOAD 425Fl48 l-lr. PWA-SZIC OXlD. CORR Run Base Fluid Cone. Wt. 4 ppl Here. A TEST WT. A. mg/Cm TAN Kin. Vise.

Cu. Mg. Inc. lnc.

l Base Fluid B Example l0.l5 3l85 l47 2 Base Fluid B Example Ill 0.]. 3Ul5 I66 -0.29 0.0 0.74 23.0 3 Base Fluid B Example II 0.15 3460 I44 +0.2l 0.0 l.ll 28.5 4 Base Fluid A Example I 0.30 3850 I84 t) Relative rating in percent obtained by running the US. Navy reference oil Base Fluid C on the front side of the gear set and the test nil on the back side of the same gear set.

8. A lubricating oil composition according to claim 1 in which said base oil is a mineral oil.

9. A lubricating oil composition according to claim 1 in which said base oil is a synthetic ester base oil.

lphenyl-a-orBnapthylamine, from about 0.5 to 2.0 percent of a dioctyldiphenylamine, from about 0.5 to 5 percent of a trihydrocarbyl phosphate and from about 10. A lubricating oil composition according to claim 5 to Percent of a Polyhydmxyamhraquinone' 1 containing from about 0.5 to 2.5 percent of an alkary- 

1. A LUBRICANT COMPOSITION COMPRISING A MAJOR PORTION OF BASE OIL HAVING LUBRICATING PROPERTIES CONTAINING FROM ABOUT 0.001 TO 0.5 WT. PERCENT OF A HYDROCARBYNL-AMMONIUM TRITHIOCYANURATE REPRESENTED BY THE FORMULA:
 2. A lubricating oil composition according to claim 1 in which said hydrocarbyl radical has from 12 to 22 carbon atoms.
 3. A lubricating oil composition according to claim 1 in which said hydrocarbyl radical is a tertiary alkyl hydrocarbon radical.
 4. A lubricating oil composition according to claim 1 in which said hydrocarbylammonium trithiocyanurate is tri(t-C18-C22 alkyl primary ammonium) trithiocyanurate.
 5. A lubricating oil composition according to claim 1 in which said hydrocarbylammonium trithiocyanurate is tri(t-C11-C14 alkyl primary ammonium, trithiocyanurate.
 6. A lubricating oil composition according to claim 1 in which said hydrocarbylammonium trithiocyanurate is di(t-C18-C22 alkyl primary ammonium, trithiocyanurate.
 7. A lubricating oil composition according to claim 1 in which said hydrocarbylammonium trithiocyanurate is di(t-C11-C14 alkyl primary ammonium) trithiocyanurate.
 8. A lubricating oil composition according to claim 1 in which said base oil is a mineral oil.
 9. A lubricating oil composition according to claim 1 in which said base oil is a synthetic ester base oil.
 10. A lubricating oil composition according to claim 1 containing from about 0.5 to 2.5 percent of an alkarylphenyl-Alpha -or Beta napthylamine, from about 0.5 to 2.0 percent of a dioctyldiphenylamine, from about 0.5 to 5 percent of a trihydrocarbyl phosphate and from about 0.05 to 0.25 percent of a polyhydroxyanthraquinone. 